Certain engines may require that the fuel be significantly pressurized in order to operate properly. For example, some types of direct-inject engines (e.g., common rail fuel injection (CRFI) in diesel engines, gasoline direct injection (GDI) in gasoline engines, etc.) may require that the fuel be pressurized to more than 1,000 psi before being introduced into the combustion chamber. In such engines, the fuel is stored in a fuel tank, is initially pumped by a low-pressure pump that delivers the fuel from the low-pressure pump to a high-pressure pump, and is then further pressurized by a high-pressure pump so that the fuel can be introduced into the combustion chamber at a significantly elevated pressure. In some instances, the high-pressure pump is mechanically coupled to and driven by the engine (e.g., a piston pump mechanically coupled to an engine camshaft).
Because the high-pressure pump is mechanically driven by the camshaft or some other engine component, as well as the fact that it is providing significantly pressurized fuel, the high-pressure pump may generate significant amounts of sound and/or vibrations that are undesirable to the occupants of the vehicle.